Masini, A.A.MasiniCOMASTRI, AndreaAndreaCOMASTRIPuccetti, S.S.PuccettiBaloković, M.M.BalokovićGandhi, P.P.GandhiGuainazzi, M.M.GuainazziBauer, F. E.F. E.BauerBoggs, S. E.S. E.BoggsBoorman, P. G.P. G.BoormanBrightman, M.M.BrightmanChristensen, F. E.F. E.ChristensenCraig, W. W.W. W.CraigFarrah, D.D.FarrahHailey, C. J.C. J.HaileyHarrison, F. A.F. A.HarrisonKoss, M. J.M. J.KossLaMassa, S. M.S. M.LaMassaRicci, C.C.RicciStern, D.D.SternWalton, D. J.D. J.WaltonZhang, W. W.W. W.Zhang2020-08-262020-08-2620170004-6361http://hdl.handle.net/20.500.12386/26839<BR /> Aims: We study the long-term variability of the well-known Seyfert 2 galaxy Mrk 1210 (also known as UGC 4203, or the Phoenix galaxy). <BR /> Methods: The source was observed by many X-ray facilities in the last 20 yr. Here we present a NuSTAR observation and put the results in the context of previously published observations. <BR /> Results: NuSTAR observed Mrk 1210 in 2012 for 15.4 ks. The source showed Compton-thin obscuration similar to that observed by Chandra, Suzaku, BeppoSAX and XMM-Newton over the past two decades, but different from the first observation by ASCA in 1995, in which the active nucleus was caught in a low flux state or was obscured by Compton-thick matter with a reflection-dominated spectrum. Thanks to the high-quality hard X-ray spectrum obtained with NuSTAR and exploiting the long-term spectral coverage spanning 16.9 yr, we can precisely disentangle the transmission and reflection components and put constraints on both the intrinsic long-term variability and hidden nucleus scenarios. In the former case, the distance between the reflector and the source must be at least 2 pc, while in the latter the eclipsing cloud may be identified with a water maser-emitting clump.STAMPAenArticle10.1051/0004-6361/2016294442-s2.0-85009469590000392392900116https://www.aanda.org/articles/aa/full_html/2017/01/aa29444-16/aa29444-16.html2017A&A...597A.100MFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation